Croatian Petra Martic's hard-fought loss to American No. 5 seed Sloane Stephens on Friday was all too much for the 28-year-old, who immediately tried to find a private place to let her emotions out after walking off court.

Australian Open TV partners around the world, including ESPN in the United States, spotted the moment the world No. 32 walked into the car park underneath Rod Laver Arena and slumped to the floor crying.

Positioned in a small corner nook of the car park, Martic sobbed uncontrollably into her towel, thinking she was alone.

Her problem was a TV camera posted directly in front of her - which captured the traumatic moment and shared it around the globe.

This was tough to watch.

Martic was overcome with emotion after the loss, having led with breaks of serve in both sets before eventually being eliminated from the tournament 7-6 7-6.

Martic's raw ache was all a bit much for some tennis commentators, who have accused TV broadcasters of going too far when they zoomed in on the gutted star in the middle of her breakdown.

ESPN tennis analyst Pam Shriver told ESPN it was "crushing" to suffer a loss under the circumstances that Martic did.

"When you're up 3-1 in both sets and you know you've had chances and this is the first major of the year, it's crushing," she said.

"You kind of want her to go to the locker room, but she just went to the first place she could find.

Another ESPN commentator said: "It's just heartbreaking to watch.

"This is just pure agony."

Martic left it all out there on the court, having broken Stephens serve as the American was serving for the match in the second set. She also threw everything she had at Stephens during the tiebreakers, but was eventually overcome 7-5 in a tight breaker.

Stephens acknowledged Martic's incredible fight at the end of their tight tussle, walking back onto court to applaud her opponent as Martic was walking off the court, clearly emotional.